This application relates to a unique system for electronically measuring the distance that a tractor and/or trailer has traveled by using a magnet attached to an axle to actuate a sensor mounted to rotate with a wheel. The sensor gathers, stores, and transmits mileage data to an output device.
Tractor-trailer vehicles are used to haul numerous types of cargo to various locations. One tractor may haul several different trailers in a single day as the tractor delivers a first trailer to one location, unloads the first trailer, picks up a second trailer and drives it to the next location, etc. Also, other tractors may be taking the unloaded trailers to new locations to be reloaded. Thus, the tractors and the trailers travel different distances resulting in different total mileages for any given day.
Because the trailers are hauled by different tractors it is often difficult to determine how many miles each trailer has traveled. Tractors have odometers which keep track of the total miles traveled by the tractor, but trailers typically do not have odometers. It is, however, important for a vehicle operator to know how many miles a trailer has traveled during a specific day and how many total miles the trailer has traveled.
The most common method that is used to keep track of trailer mileage is a mechanical odometer that is well known in the art. Mechanical odometers, however, are expensive, relatively inaccurate and unreliable, and prone to damage and theft. Furthermore, mechanical odometers are typically installed on a trailer axle, thus making the visual extraction of mileage readings inconvenient. An electronic odometer has been proposed as an attachment to a wheel hub. This electronic hub odometer requires a complex pivotally suspended mounting means to operate properly. As a result, this electronic hub odometer is expensive and prone to failure.
In a disclosed embodiment of this invention, an axle assembly is integrated with an electronic odometer. The axle assembly includes an axle defining an axis, a wheel assembly rotatably supported on the axle for rotating relative to the axle axis, a magnet, a sensor responsive to the magnet for producing a count signal, and a microprocessor for receiving count signal data, calculating the distance the wheel assembly has traveled, and transmitting distance data to an output device. The sensor is mounted to either the wheel assembly or the axle and the magnet is mounted to the other of the wheel assembly and the axle.
In a preferred embodiment of this invention, the magnet is mounted to the axle at a position which is eccentric to, or radially offset from, the axle axis. The sensor is mounted to the wheel assembly in radial alignment with the magnet such that rotation of the wheel assembly aligns the sensor for magnetic interaction or responsiveness to the magnet once per revolution of the wheel assembly.
The present invention provides a reliable and inexpensive solution to the shortcomings of prior art hub odometers. The inventive integrated axle and odometer assembly provides quick and convenient access for data extraction. Further, the inventive electronic odometer design can be easily installed or retrofit onto to current axle assemblies.
These and other features of the present invention will be best understood from the following specification and drawings, the following of which is a brief description.